In a passenger bridge apparatus, there are provided with movable tunnels comprising at least a first tunnel fixedly mounted and a second tunnel movable back and forth relative to the first tunnel. The first tunnel has a rear end hinged to a rotatable platform and a front end extending into and being coupled with the second tunnel via a nylon slider (roller) device so as to enable the second tunnel to move back and forth relative to the first tunnel, thereby realizing a telescopic motion of the tunnels. A transition board is provided in the first tunnel at a transition area between the first and second tunnel, in order to eliminate the effect of the height difference between the two tunnels and seal the clearance between them, thereby improving the aesthetics of its appearance.
A transition board apparatus for a passenger bridge in the prior art is shown in FIG. 1. A hinged end 131 of a transition board 13 is articulated to an end of a first tunnel bottom plate 11 via a hinge 14. The transition board 13 can rotate around the axis of the hinge 14. Provided that a free end 132 of the transition board 13 directly rests on a bottom plate ornament 121 arranged on a second tunnel bottom plate 12, when the second tunnel is moving back and forth relative to the first tunnel, a sliding friction will occur between the free end 132 of the transition board 13 and the bottom plate ornament 121, thus the bottom plate ornament 121 can be worn out. To avoid the above-mentioned occurrence, a pair of elastic support members 15 is soldered on the bottom surface of the first tunnel bottom plate 11. The support members 15 extend to the bottom of the transition board 13. An adjusting bolt 151 is arranged at the end of the support member 15 and used to raise the transition board 13 up, so that the free end 132 of the transition board 13 does not contact with the bottom plate ornament 121. The adjusting bolt 151 can be adjusted as required so as to adjust the distance between the free end 132 of the transition board and the bottom plate ornament 121. This structure can effectively avoid the friction between the free end 132 of the transition board and the bottom plate ornament 121. However, the support members 15 and the adjusting bolts 151, which are located under the transition board, make the adjustment inconvenient. Furthermore, the adjusting bolts 151 are prone to become loose and function less effectively. Therefore, it is necessary to provide an improved tunnel transition board apparatus to overcome the above deficiencies.